Hello,
that would be nice:
The enthalpy exchanger, according to my understanding, always balances the moisture between both sides (because it has a membrane that lets water vapor molecules through). This should work like with heat in both directions (exhaust air-fresh air / fresh air-exhaust air), always from the side with higher vapor pressure to the side with lower vapor pressure.
first of all, I wouldn’t be sure whether the membrane lets water molecules through equally in both directions, there are definitely membranes that work like a one-way street.
Then, such a thing only works up to equilibrium. With tricks in the heat exchanger design, you can shift the equilibrium a bit
but not to the extent that water would nicely accumulate in the exhaust air while the supply air remains dry.
And the vapor pressures would also have to be quite similar. The outside air is about 20 °C at 60-70 % relative humidity and the exhaust air is 23.5 °C at 50-55 % relative humidity. I don’t have time to calculate it in detail right now but there aren’t worlds of difference.
As I said, such an enthalpy exchanger is meant to balance extreme imbalances (mostly in winter) and thus humidify the dry outside air. It doesn’t really work as a dehumidifier. Or why do they still always include an air dryer in air conditioning systems if it would be that much easier...?
Best regards,
Andreas